Abstract
This paper is devoted to controls and observers design based on backstepping and sliding modes, for non linear systems. This method is applied to the dynamics of an underwater glider that has been developed and operated by ENSIETA. The glider dynamics can be derived from flight dynamics equations. In the framework of this paper, we are interested by the lateral equation of motion which describes the lateral motion dynamics. First, we design a roll controller. Then, we consider that we don't know the derivative of the roll required by the controller and we show how to construct a sliding mode observer in presence of the controller.